Foreign policy challenges are intruding on President Barack Obama's promise to focus on the economy after the Democrats' election debacle and threatening to knock the White House off message altogether.

The escalation of tensions between North and South Korea this past week capped a postelection period that included two presidential trips abroad, discussions about America's future in Afghanistan and a debate in Washington over Senate ratification of a nuclear treaty with Russia.

The risk for Obama is that the capital and energy spent on a foreign crisis can undermine the perception that he's working on the public's top priority: finding jobs at home for Americans.

White House officials say the international focus hasn't diminished the amount of time Obama spends working on the economy. Aides acknowledge that events abroad can make it more difficult to spotlight Obama's economic message — one of an economy on a slow but steady march toward recovery, and a president aware that his political future rests on his ability to speed that recovery.

Take Obama's trip to Kokomo, Ind., last Tuesday, his first domestic trip since the Nov. 2 elections.

By the time Obama arrived at a Chrysler plant to promote the revival of the U.S. auto industry, attention had turned to how the White House would respond to North Korea's artillery attack against a South Korean island.

"You learn quickly as president that there are events that happen like North Korea that you have to address as they happen, not how you would plan for them to happen," White House spokesman Robert Gibbs said.